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Sony str v45 reciever won't power on. Lights out when phono input was pressed. Replaced fuse...nothing. any ideas?

Sony str v45 reciever won't power on. Lights out when phono input was pressed. Replaced fuse...nothing. any ideas?

helio4113

Did you install the new fuse and it doesn't power up? Is the fuse blown again? Disconnect the turntable and try again with the tuner..


hairyanus47

The new one is ceramic so I cant tell. I tried with tuner still nothing.


helio4113

Is probably blown again, you might have a short somewhere..


madscientistEE

If the second fuse blows, do not install a another one until the short circuit is located. Repeated overloads may cause additional damage. That 3.15A fuse is probably the main power fuse. Something has probably put a direct short across the power supply. The most likely culprits are the output transistors but it could possibly be the filter capacitors or the rectifier as well. You need to test the output transistors Q706, Q707 and Q756, Q757. Those will be mounted to the largest heatsink in the unit. If ANY of those are bad, you will need to test all the other transistors and diodes in the power amp for the channel with bad output transistors. If both sides have bad outputs, all diodes and transistors on the entire power amp board will need to be checked. There are also a number of fusible resistors you will need to test. Any transistor connected to a blown fusible resistor should be changed even if it tests OK as it may have been exposed to currents outside of its design limit. Service manual for the STR-V45L is here, registration is free: [https://www.hifiengine.com/manual\_library/sony/str-v45.shtml](https://www.hifiengine.com/manual_library/sony/str-v45.shtml) (The L version manual can be used to fix the non L version as well. L version is the same as non L with the exception of a European style 220-240V power supply and the inclusion of a long wave tuner in addition to the usual medium wave AM. Longwave AM is not commercially broadcasted in North America, hence why the 120V versions only have "AM" and not separate LW and MW bands.)


hairyanus47

Thank you for the reply. I am not familiar with electronics repair. so no better time to learn. What do I need a voltage meter and what else?


RecipeForIceCubes

Basics... soldering iron, 60/40 rosin core solder, desoldering wicks/extractor pump, magnifying glass, needle nose pliers, small screwdrivers, steady hands. An easy way to practice soldering is to go to Goodwill or wherever and buy a few old clock radios/VCRs, anything electronic. Make sure it works and practice un-soldering and resoldering transistors, capacitors...If it works when you've tinkered around for a while then you're off on the right foot.


madscientistEE

If you want to get into the hobby, get decent tools. Don't get the cheapest multimeter you can find....it not only helps you troubleshoot, it keeps you safe. Learn to use your multimeter well before making repairs on expensive gear or anything that could shock you. Getting a meter with "True RMS" capability is not only useful for audio work, it weeds out the vast majority of unsafe trash meters that aren't worth the plastic they're made of. True RMS actually samples the incoming AC wave instead of blindly assuming the signal measured is a perfect sine wave. This makes for more accurate readings in the presence of noise or distortion. Decent models start in the $35 range. (https://www.amazon.com/AmazonCommercial-Count-Compact-Digital-Multimeter/dp/B07W1BL1W6 is a decent place to start and doesn't have questions as to if the safety features actually work!) You'll want an expanded set of test leads for various situations. The lead set costs as much as some meters but crap leads can cause issues with tests and are unsafe as well. I own these and I like them. https://www.amazon.com/Meterk-Electronic-Multimeter-Replaceable-Accessories/dp/B07BDF6CVT